WO2019020164A1

WO2019020164A1 - Electric tool and method for identifying a kickback event of an electric tool

Info

Publication number: WO2019020164A1
Application number: PCT/EP2017/068648
Authority: WO
Inventors: Markus Schmid; Marc RUSCH
Original assignee: Festool Gmbh
Priority date: 2017-07-24
Filing date: 2017-07-24
Publication date: 2019-01-31
Also published as: CN111093921A; CN111093921B; KR20200031621A; US20210154758A1; US20220009012A1; US20220016723A1; EP3621777B1; US11701723B2; KR102434522B1; DK3621777T3; EP3621777A1; JP2020529928A; JP7050897B2; US11491564B2

Abstract

The invention relates to an electric tool (10; 20; 30) comprising a rotatable tool (1) embodied as a saw blade or mill, provided with a sensor device (2) for detecting a mechanical variable (3), the mechanical variable (3) comprising a force, an acceleration, a speed, a deviation, a deformation and/or a mechanical tension, said mechanical variable (3) depending on a force exerted by the tool (1), said electric tool also comprising a control device (4) that is communicatively coupled to a sensor device (2) and is designed to identify a kickback event on the basis of the detected mechanical variable (3), the control device (4) being designed to selectively determine, on the basis of function-determining information, a first identification function or a second identification function that is different from the first identification function, and to carry out the identification of the kickback event based on the detected mechanical variable, using the determined identification function.

Description

ELECTRICAL TOOL AND METHOD FOR RECOGNIZING A KICKBACK EVENT OF AN ELECTRICAL TOOL

The invention relates to a power tool with a trained as a saw blade or cutter rotatable tool, a sensor device for detecting a mechanical variable, wherein the mechanical size of a force, a

Acceleration, a speed, a deflection, a deformation and / or a mechanical stress and the mechanical size depends on a force emanating from the saw blade, as well as one with the sensor device

communicatively coupled controller that is configured based on the detected mechanical quantity

Detect kickback event of the power tool.

By the term "kickback event" is meant in particular an event in which during the machining of a workpiece by the power tool, a sudden and unexpected force between the power tool and the

Workpiece occurs through which the power tool or the workpiece is then accelerated and set in motion. In table saws, kickback usually results in unexpected acceleration of the workpiece towards the user. With circular saws it can come with a kickback to unexpected movements of the tool. Kickbacks can cause injury to the user and therefore compromise operational safety

Kickback event can be especially jerky, too rapid dipping of the tool into the workpiece, backward sawing, jamming of the tool in the workpiece, for certain workpiece properties (eg

inhomogeneous wood, stresses) and / or occur with a blunt tool.

WO 2014/105935 A1 describes a table saw with a kickback detection system, which comprises a sensor which is designed to detect a deflection of a shaft as a scalar quantity. A controller compares the sensed displacement with a scalar threshold

determine if there is a kickback.

An object of the invention is to modify the aforementioned power tool so that the

Usability of the power tool is improved.

The object is achieved by a power tool according to claim 1. According to the invention, the control device

educated, based on one

Function determination information optionally a first

Detection function or one of the first

Detection function to determine different second detection function and the recognition based on the detected mechanical size detection of the kickback event below

Using the specific detection function.

The controller is thus able to determine one of at least two different recognition functions to recognize the kickback event. The

Control device are therefore different

Detection features that she can use. The controller determines one of these

Detection functions and uses the specific

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July 24, 2017 Detection radio to perform the detection of the kickback event.

Due to the fact that the control device is different

Detection functions are available and one of

Detection functions based on the

Function determination information is determined may

be enabled that in terms of a current operating and / or environmental condition optimal

Detection function is used. For example, the function determination information (and thus the recognition function to be used) may be provided based on which user is using the power tool, what tool is being used, and / or what workpiece is to be machined.

If the current user is, for example, a particularly inexperienced user, then a particularly sensitive or sensitive recognition function can be determined in order to ensure that in particular even weak kickbacks are recognized by the control device. For a particularly experienced user, on the other hand, it is advisable to have a particularly insensitive recognition function

determine so that only very strong kickbacks are detected and an unnecessary interruption of processing is avoided.

By optionally determining a recognition function of at least two different from each other

Detection functions can therefore improve the usability of the

Power tool can be improved.

Conveniently, the control device is designed for the detection of the kickback event only one - namely the

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July 24, 2017 previously intended to use - detection function. This means that the control device is preferably designed to use either only the first or only the second recognition function to recognize the kickback event.

Advantageous developments are the subject of

Subclaims.

The invention further relates to a system comprising the power tool discussed above and an external device, in particular a server. The power tool is designed to provide operating and / or environmental information to the external device and / or a

To transmit user identification information. The external device is formed based on the

Operating and / or environmental information and / or the

User identification information

Provide functional determination information and transmit it to the power tool.

The invention further relates to a method for detecting a kickback event of a power tool with a rotatable tool designed as a saw blade or cutter. The method comprises the steps of: detecting a

mechanical quantity, wherein the mechanical quantity comprises a force, an acceleration, a velocity, a deflection, a deformation and / or a mechanical tension and the mechanical size depends on a force emanating from the tool, based on a

Function determination information, one to be used

Detection function of a first recognition function and a second recognition function and recognition different from the first recognition function, using the

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July 24, 2017 certain detection function, the kickback event based on the detected mechanical size.

Conveniently, the method with a here

described power tool performed.

Further exemplary details as well as exemplary

Embodiments will be explained below with reference to the drawings. It shows a schematic representation of a

Power tool, a diagram illustrating a kickback detection based on a direction of a mechanical vector size, a sectional view of a power tool, a sectional view of an output shaft and two bearings of the power tool, a schematic representation of a

Power tool, and a block diagram of a method.

FIG. 1 shows a power tool 10 according to a first embodiment.

The power tool 10 has an example designed as a saw blade rotatable tool 1. Alternatively, the tool 1 may also be designed as a milling cutter. The power tool 10 includes a sensor device 2 for detecting a mechanical quantity 3. The mechanical size

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July 24, 2017 includes a force, an acceleration, a

Speed, deflection, deformation and / or stress. The mechanical quantity 3 depends on a force emanating from the tool 1. The

Power tool also has a with the

Sensor device 2 communicatively coupled control device 4. The control device 4 is designed to detect based on the detected mechanical variable 3, a kickback event.

The controller 4 is configured to selectively set a first based on a function determination information

Detection function or one of the first

Detection function to determine different second detection function. The controller 4 is further configured to perform the detected mechanical magnitude based detection of the kickback event using the determined detection function.

Due to the fact that the control device 4 is able to select one of several available recognition functions

In principle, it is possible to use a recognition function which is as suitable as possible for a current state and thus to determine the recognition function and to use it to recognize the kickback event

Usability of the power tool 10 to improve.

The following are exemplary details of the

Power tool 10 and other exemplary

Embodiments explained.

The power tool 10 is preferably a saw, in particular a circular saw or a

Circular saw. The power tool 10 can also be used as

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July 24, 2017 Flachdübelfräse be formed. The tool 1 is

in particular circular and rotates during operation

exemplary clockwise.

As an example, the power tool 10 has a housing

6, in which in particular the sensor device 2 and the

Control device 4 are arranged. The control device 4 is designed for example as a microcontroller. On the housing 6, a support surface 9 is provided with which the power tool 10 can be placed on a workpiece 11 to be machined.

The power tool 10 has a drive device

7. The drive device 7 includes, for example, an electric motor and a transmission. The drive device 7 is preferably controlled by the control device 4. The power tool 10 further has an output shaft 8, which can be driven by the drive means 7. The tool 1 is mechanically coupled to the output shaft 8. Conveniently, the tool 1 on the

Output shaft 8 attached.

As shown in FIG. 1, during machining of the workpiece 11, the power tool 10 typically rests on the workpiece 11 with the support surface 9 and is moved in a feed direction 12 relative to the workpiece 11.

As an example saw teeth saw as a saw blade

trained tool 1 while from bottom to top in the workpiece 11. In this constellation, the tool 1 urges relative to the rest of the power tool 10 by way of example in the direction of the drawn mechanical size 3, ie obliquely downward. The force emanating from the saw blade 1 in particular points in the direction of the mechanical variable 3.

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July 24, 2017 The power tool 10 further has a support structure 21, which is expediently arranged in the housing 6. On the support structure 21, for example, the output shaft 8 is mounted. Furthermore, the support structure 21 may be formed as a housing for the drive device 7. The support structure 21 may, for example, constitute or comprise a drive housing, in particular a transmission housing.

By way of example, the power tool 10 also has a user input device 5. By means of

User input device 5, the user can a

User input, for example, the

Power tool 10 on and off and / or

configure and / or calibrate.

Furthermore, the power tool 10 has an exemplary communication interface 35. The

Communication interface 35 is used for communication with an external device 38, in particular an external server and / or a mobile device. The

Communication interface 35 is in particular to

wireless and / or wired communication

educated. For example, the

Communication interface 35 is designed to communicate via Ethernet, WLAN, Bluetooth and / or NFC.

Furthermore, the power tool 10 has an example of a user identification device 36. Die

User identification device 36 is designed to record user identification information, expediently a property, in particular a biometric property, of a user so as to enable an identification of the user, for example by the control device 4. The user identification device 36

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July 24, 2017 has, for example, a fingerprint scanner and / or an image sensor.

The sensor device 2 has two examples

Sensor units 33, 34. The above-mentioned detection of the mechanical variable 3 is carried out by way of example by the first sensor unit 33. In FIG. 1, the sensor device 2 or the first sensor unit 33 is shown as an example

Output shaft 8 coupled and formed, the mechanical size 3 - namely a force, acceleration,

Speed, deflection, deformation and / or mechanical tension - to detect the output shaft 8. Expediently, the detected mechanical variable 3 is a vector variable. Preferably, the sensor device 2 is designed to detect the mechanical variable 3 continuously, so that a change, in particular a

Direction change of the mechanical size 3 can be detected.

The sensor device 2 is preferably also designed to record operating and / or environmental information. For this purpose, the sensor device 2 in FIG. 1 optionally has the second sensor unit 34. Alternatively or additionally, it is also possible for the detection of operating and / or environmental information to be the first one

Sensor unit 33 to use.

The operating and / or environmental information is, for example, a property of the tool 1, for example the type and / or a state of wear of the tool

Tool 1.

By way of example, the sensor device 2 as the second sensor unit 34 can comprise an image sensor, with which an image

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July 24, 2017 of the tool 1, in particular a marking applied to the tool 1, for example one

Type designation, can be included. Based on the recorded image, the control device 4 can then determine the type of the tool 1.

In order to determine a state of wear of the tool 1, the control device 4 can be designed, for example, to detect the mechanical variable 3 as a mechanical vector variable and to conclude the state of wear for a specific direction and / or change in direction of the mechanical vector variable. Alternatively or additionally, the

Control device 4 may be formed, which detected

mechanical size 3 over a longer period of time or a variety of uses of the power tool 10 away

to record repeatedly and make a statistical evaluation of the observations, from which then to the

Wear state can be closed, for example, based on a trend or a deviation of a mean value.

Furthermore, as an operating and / or environmental information, a property of the workpiece 11 to be machined with the tool 1 can be detected. For example, an image of the workpiece 11, in particular a marking 37 mounted on the workpiece 11, for example a

Type designation to be included. Based on the recorded image, the control device 4 can then determine the type of the workpiece 11.

Furthermore, the recorded operating and / or

Environment information a temperature and / or a

Humidity include. The sensor device 2 may, for example, as the second sensor unit 34 a

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July 24, 2017 Temperature sensor and / or include a humidity sensor.

In the example shown, it is the second

Sensor unit 34 and the user identification device 36 by two different units. Alternatively, especially when both the sensor unit 34 and the user identification device 36 are used to record an image, the sensor unit 34 and the user identification device 36 may also be one and the same unit.

Below are the two detection functions and in particular the difference between the

Detection functions explained in more detail.

In the simplest case, the detection functions may each be a comparison of the mechanical variable 3 with a respective one performed by the control device 4

Act threshold. For example, the mechanical quantity 3 is detected as a scalar and compared with a respective scalar threshold value. Alternatively or additionally, the mechanical quantity 3 can also be detected as a vector variable and the magnitude of the vector variable can be determined with a

respective threshold. Will the

Threshold exceeded, so does the

Control device 4 to a kickback event.

Each detection function is suitably associated with a different threshold. For example, the

Threshold of the first detection function greater than the threshold of the second detection function.

30113 / PCT. July 2017 Preferably, the second detection function is more sensitive or sensitive than the first detection function. This means that when using the second recognition function, a larger value range of the detected mechanical quantity 3 leads to the recognition of a kickback event than in the first recognition function.

The second detection function is therefore more suitable, for example, for less experienced users of the power tool, since the second detection function recognizes a larger range of kickbacks-in particular also weaker kickbacks. By contrast, the first recognition function, for example, is better suited for experienced or very experienced users of the power tool 10, who can deal with weaker kickbacks without assistance from the power tool 10. Since the first detection function does not recognize or ignore weaker kickbacks, the use of the first detection function can prevent an experienced or very experienced user from making unnecessary and disruptive interruptions to the machining process due to the kickback detection.

As already mentioned above, the mechanical variable 3 is preferably detected as a vector quantity. The kickback event in this case can be recognized in particular based on a direction and / or a change in the vector size. For example, the control device 4

trained to determine if the direction of a

Vector size detected mechanical size 3 lies within or outside a certain directional range and

based on this determination to decide whether the kickback event is present or not.

30113 / PCT. July 2017 With reference to FIG. 2, a vector-size-based recognition of the kickback event will be explained in more detail below.

Figure 2 shows a diagram with different

Directional areas 14, 15 and the detected mechanical size 3.

The diagram is divided into four quadrants. Everyone

Quadrant includes 90 degrees. Reference numeral 19 denotes the zero-degree line. The below mentioned

Angular coordinates or degrees are to be understood in the mathematically positive sense of rotation (counterclockwise).

Conveniently, the zero-degree line runs parallel to the support surface 9 and / or to the feed direction 12th

The directional areas 14, 15 are

exemplified by two-dimensional directional areas. The

Directional regions 14, 15 may also be referred to as angular regions. Conveniently, the lie

Directional areas 14, 15 in one plane. The plane is expediently oriented parallel to the plane of the tool 1 or perpendicular to the axial direction of the output shaft 8.

The two directional areas 14, 15 differ from each other. By way of example, the first directional area 14 lies within the second directional area 15. The first

Directional range 14 is expediently smaller than the second directional range 15.

Expediently, the first directional area 14 is associated with the first recognition function. The first

Detection function comprises in particular a comparison of a direction of the mechanical vector size with the first one

30113 / PCT. July 2017 Directional area 14. Furthermore, the second Richtungsreicht 15 is suitably associated with the second detection function. In particular, the second recognition function comprises a comparison of the direction of the mechanical vector size with the second directional range 15.

The control device 4 is expediently designed, the first directional range 14 and the second

Provide directional range 15. For example, both directional areas are in a memory in the

Control device 4 is stored. Alternatively or additionally, the control device 4 may also be designed to generate the directional regions 14, 15 themselves.

The first directional range 14 represents a directional range in which the mechanical vector size lies when there is a very high probability of a kickback or

imminent. By way of example, the first directional region 14 is located in the two upper quadrants, ie within a range between 0 degrees and 180 degrees. In the example shown, the first directional range 14 extends from 5 degrees to 100 degrees. If the control device 4 uses the first recognition function, the kickback event is recognized if the mechanical vector quantity 3 lies in the first directional range 14.

The second directional region 15 is opposite to the first

Direction range 14 increased. By way of example, the second directional region 15 is located in the first, second and fourth quadrants, ie within a range between 270 degrees (or -90 degrees) and 180 degrees. In the shown

For example, the second direction range 15 extends from 340 degrees (or -20 degrees) to 120 degrees. The second

Directional range 15 includes not only directions in which

30113 / PCT. July 2017 with a very high probability of a kickback

can be assumed, but beyond

Directions where kickback is still possible, but less likely than in the first direction region 14. In particular, the second directional range 15 also includes directions in which the cause or a first indicator for the kickback already exists, but the power tool 10 or the workpiece 11 is not yet significant

have been accelerated or have not yet carried out a recoil or setback. Conveniently, the control device may be configured to kick-start the event when using the second directional range 15 50 to 100 ms before (without detection and reaction to the kickback) occurring

Acceleration of the power tool 10 relative to the

To recognize workpiece 11. The acceleration is, for example, an acceleration with a

Component up or a component in 90-degree direction in the diagram shown.

The control device is expediently designed to recognize that there is no kickback event if the mechanical variable 3 lies outside the first directional range 14 or the second directional range 15.

Alternatively or in addition to the recognition of the kickback event described above based on the direction of the detected mechanical vector magnitude, it is also possible to perform the kickback event based on a directional change of the mechanical vector magnitude.

The first and second detection functions can

Accordingly, a comparison of a change in direction, in particular an angular velocity and / or a

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July 24, 2017 Change angles comprising mechanical vector magnitude with a respective direction change threshold.

If kickback is imminent, the mechanical vector magnitude will turn toward the first

Directional range 14. The detection functions can

Accordingly, a detected rotation of the mechanical

Consider vector size when detecting the kickback event. By way of example, the control device 4 is designed to compare the angular velocity of the mechanical vector variable with a velocity threshold value and, when the velocity is exceeded

Speed threshold to detect the kickback event. In the first recognition function can thereby another, especially a larger

Speed threshold can be used as the second detection function.

Furthermore, the control device 4 can be designed to determine what angle of change the mechanical vector variable 3, in particular within a certain

Time window and compare this angle of change with an angle threshold to detect the kickback event. In the first recognition function can thereby another, especially a larger

Angle threshold can be used as the second detection function.

In addition, the recognition functions can be the duration

take into account that the mechanical vector size 3 is within a certain directional range 14, 15. For example, the controller 4 may be configured to detect the kickback event only if the mechanical vector size is longer than a certain one

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July 24, 2017 Time threshold in a certain direction range 14, 15 is. In the case of the first recognition function, a different, in particular a larger time threshold can be used

used as the second detection function.

The above-explained concrete angle data of

Directional areas 14, 15 are to be understood as purely exemplary. Depending on the type and construction of the power tool 10, the actual angles may vary. The actual angles of the directional regions 14, 15 can be determined by means of calibration

be determined. The calibration may be, for example, during the development or manufacture of the power tool

and / or done by the user.

Expediently, the control device 4 is designed to carry out a calibration of one or more directional regions 14, 15. For example, by means of

User interface 5 the calibration can be initiated. The controller 4 can then on the

Drive device 7, the tool drive 1 and thereby via the sensor device 2, the mechanical vector size third

to capture. Based on the detected mechanical

Vector size 3, the controller 4 then a

Create direction range and / or one or more thresholds and store in a memory of the controller 2.

Below is explained by way of example how to

can be determined using the recognition function.

Basically, the control device 4 determines the

using recognition function based on the

Function determination information. The

Function determination information is given to the control device 4

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July 24, 2017 either provided externally or in the

Control device 4 created.

For example, the function determination information may be input through the user input device 5.

As an example, a user can use the

User input device 5 between two different security profiles - e.g. a beginner profile and a professional profile - choose. According to the entry or choice of the

User then uses the controller 4 either the first recognition function or the second recognition function.

Furthermore, the control device 4, the

Function determination information about the

Communication interface 35 received. For example, the control device 4 can communicate with an external device 3, for example a server or a mobile device, via the communication interface, and the function determination information from this external device 3

get provided. According to the received

Function determination information uses the

Control device then either the first detection function or the second detection function.

By way of example, the function determination information can also be provided in the control device 4. For example, the control device 4 is formed by means of

User identification device 36 to identify a user and provide the function determination information according to the identification. For example, an association between different users and the recognition functions can be stored in the control device 4, so that when the user has been identified, the associated recognition function can be selected and used.

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July 24, 2017 By way of example, the control device is further embodied, the function determination information based on a signal generated by the sensor device 2, in particular the second

Sensor unit 34, recorded operating and / or

Provide environmental information. For example, by means of the sensor device 2, the control device 2 can determine a state of the tool, workpiece and / or the environment and, based thereon, the state to be used

Determine recognition function.

It is also possible for the control device 4 to identify the user and / or to provide the function determination information about the user

Communication interface 35 with the external device 38, in particular the server or mobile device, cooperates. The power tool 10 and the external device 38 may together form a system in this case. The power tool 10 is designed, for example, to transmit to the external device 38 operating and / or environment information and / or user identification information.

Conveniently, the external device 38 is configured based on the operational and / or environmental information and / or user identification information

Provide functional determination information and transmit to the power tool.

For example, as the

User identification information with the

User information device, such as biometric information, are transmitted to the external device 38. In the external device 38, a user identity and / or a function determination information can then be determined, for example, using a database stored there. The

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July 24, 2017 User identity and / or the

Function determination information may then be provided via the

Communication interface 35 are transmitted to the control device 4 for further use.

In the discussion above, there are always two

Detection features mentioned. Of course, the control device 4 but also more than two different detection functions for detecting the kickback event are available.

Those of the control device 4 available

Detection functions can be stored, for example, in a memory of the control device 4. According to the

Function determination information, the controller 4 then selects a recognition function and uses this to detect a kickback event. The

Function determination information in this case may be e.g. the information includes which recognition function to use.

Alternatively or additionally, the control device 4 can also create a recognition function to be used itself, expediently based on the

Function determination information. The

Function determination information may include, for example, a parameter to be used for the recognition function,

for example, a threshold, and / or one too

specify the mathematical operator used.

Hereinafter, exemplary ways are explained how the mechanical quantity 3 can be detected as a vector quantity.

30113 / PCT. July 2017 The sensor device 2 is expediently designed, the mechanical vector size 3 than at least

capture two-dimensional vector. For this purpose, the sensor device 2 is formed, which is the mechanical

Vector size 3 underlying mechanical size in

to measure at least two different spatial directions. The two spatial directions are, for example, a spatial direction which runs parallel to the feed direction 12 and a spatial direction perpendicular to the direction of travel

Feed direction 12 extends. Expediently, both spatial directions are perpendicular to the axial direction of the output shaft 8. For example, the sensor device 2 has at least two sensor elements 25, 26. Expediently, each of the sensor elements 25, 26 serves the underlying mechanical variable - ie a force, a

Acceleration, a speed, a deflection, a deformation and / or a mechanical tension to measure in another spatial direction.

The mechanical vector size 3 is in particular a

Force vector, an acceleration vector

Velocity vector, a displacement vector, a

Deformation vector and / or a mechanical stress vector or stress tensor. Accordingly, the

Sensor device 2 may be formed in at least two spatial directions a force, an acceleration, a

Speed, a deflection, a deformation and / or a mechanical tension to measure.

The sensor device 2 can in particular a radial

Measuring bearing 28 include, with the example, the

Output shaft 8 is mounted. The radial measuring bearing 28 may be formed by force or voltage sensors, such as piezoresistors, the force between

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July 24, 2017 the output shaft 8 and the measuring bearing 28 to be detected as the mechanical vector size 3.

Alternatively or additionally, the sensor device 2 distance sensors spaced from the output shaft 8

which are formed, the deflection of the

Output shaft 8 as the mechanical vector size 8 to

to capture .

Furthermore, the sensor device 2 in particular at the

Support structure 21 attached voltage sensors, in particular strain gauges (DMS) include.

In principle, the sensor device 2 can be set up to measure the mechanical vector size 3 at any part within the force flow emanating from the tool 1. The power flow runs as an example from the tool 1 via the output shaft 8, a bearing device 27, the support structure 21, the housing 6 and the bearing surface 9 to the workpiece 11. In particular, the sensor device 2 is formed, the mechanical vector size 3 between two in the power flow one behind the other To measure parts.

FIG. 3 shows a sectional view of the FIG

Power tool 20. The above related to the power tool 10 embodiments also apply to the power tool 20th

As shown in FIG. 3, the power tool 20 comprises a bearing device 27 which is attached to the support structure 21

is provided and the output shaft 8 with respect to the

Supporting structure 21 stores. The bearing device 27 expediently comprises one or more bearings 31, 32, in particular radial and / or Radiaxlager, preferably ball bearings.

30113 / PCT. July 2017 Conveniently, at least one bearing 31, 32 of

Storage device 27 as a measuring bearing 28, in particular radial measuring bearing, is formed and can therefore as the

Sensor device 2 serve. Preferably, the measuring bearing 28 is formed, one between the output shaft 8 and the

Support structure 21 present force in at least two

to measure different spatial directions. For example, the measuring bearing 28 has a plurality of

Sensor elements, such as piezoresistive

Sensor elements, in particular piezoresistive

Thin-film sensor elements, which expediently in

Circumferentially arranged around the output shaft 8 around. In particular, the sensor elements are on an outer

Bearing component of the measuring bearing 28 - that is a stationary relative to the support structure 21 bearing component or a not co-rotating with the output shaft 8 bearing component, such as an outer ring arranged. As an example, eight sensor elements are provided, which are each offset by 45 degrees to each other.

FIG. 4 shows the output shaft 8 together with two

By way of example, the first bearing 31 is arranged in the region of a distal end of the output shaft 8 assigned to the tool 1, and the second bearing 32 is arranged in the region of a distal end of the output shaft 8 facing away from the tool 1.

Conveniently, one or both bearings 1, 2 is formed as the measuring bearing 28 explained above.

Alternatively or in addition to the above-described embodiment, in which the sensor device 2 is integrated on the inside in one or more bearings 31, 32, the

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July 24, 2017 Sensor device 2 may also be arranged between one or more bearings 31, 32 and the support structure 21.

FIG. 5 shows a power tool 30 according to a sixth embodiment. The power tool 30 is exemplified here as a stationary saw, in particular as a table saw

educated. The power tool 30 advantageously includes the above already in connection with the

Power tool 10 and / or the power tool 20

discussed features.

By way of example, the tool 1 rotates here in

Counterclockwise. The workpiece 11 is expediently pushed into the tool 1 designed as a saw blade during machining in such a way that the saw teeth saw from top to bottom into the workpiece 11. In the figure 8 a corresponding feed direction 12 is located. The

Directional areas 14, 15 are adapted accordingly in the power tool 60. For example, the directional regions 14, 15 shown in FIG. 2 may be point-mirrored about the center of the diagram.

In the following, various options are discussed how to react to a recognized kickback event. Conveniently, each of these options may be provided in any of the power tools discussed above.

Preferably, the controller 4 may be configured to respond in response to the detected kickback event

make certain control of the drive device 7, for example, to cause the tool 1 is no longer driven and / or braked, in particular completely braked. The braking can be done in particular with the same electric motor, with which the tool 1 otherwise

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July 24, 2017 is driven. Alternatively or additionally, the drive device 7 may comprise a braking means and the

Control device 4 may be configured to control the braking means in response to the detected kickback event so that the tool 1 is braked.

Furthermore, the power tool 10, 30 a

Positioning device 29 include, which is formed, the tool 1 either in an operating position or a

Position safety position. The controller 4 may be configured in response to the detected

Kickback event the positioning device 29 to control, so that the tool 1 in the safety position

is positioned. The positioner 29 is

for example, designed to move the tool 1 between the operating position and the safety position and / or pivot. Expediently, the tool 1 is in the safety position further into the housing 6

positioned as in the operating position.

FIG. 6 shows a flow chart of a method for detecting a kickback event of a power tool with a rotatable tool designed as a saw blade or milling cutter. The method comprises the steps: detecting, Sl, a mechanical quantity 3, wherein the mechanical quantity 3 a force, an acceleration, a speed, a deflection, a deformation and / or a mechanical

Includes stress and the mechanical quantity 3 depends on a force emanating from the tool 1, determining, S2,

based on function determination information, a recognition function to be used from a first one

Detection function and one of the first

Detection function different second detection function and detecting, S3, using the specific

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July 24, 2017 Detection function of the kickback event based on the detected mechanical quantity 3.

Appropriately, the method by means of one of the above-described power tools 10; 20; 30

executed.

Preferably, the method has a further step in which one of the above-discussed responses to the detected kickback event is executed.

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July 24, 2017

Claims

claims

Electric power tool (10, 20, 30) with a rotatable tool (1) designed as a saw blade or milling cutter, comprising a sensor device (2) for detecting a mechanical variable (3), wherein the mechanical variable (3) is a force, a

Acceleration, speed, deflection, deformation and / or stress and the mechanical size (3) of one of the tool (1)

outgoing power, as well as one with the

Sensor device (2) communicatively coupled

Control device (4) which is designed to detect a kickback event on the basis of the detected mechanical variable (3), wherein the control device (4) is designed to optionally display a first detection function or one of the first based on function determination information

Using the specific detection function.

2. Electric tool (10; 20; 30) according to claim 1, characterized in that the two detection functions differ in their sensitivity.

3. Power tool (10; 20; 30) according to claim 1 or 2, characterized in that the first detection function a comparison of the detected mechanical variable (3) with

P 30113 / PCT - dr

July 24, 2017 a first threshold value and the second detection function comprises a comparison of the detected mechanical quantity (3) with one of the first threshold value

different second threshold.

4. Power tool (10; 20; 30) according to one of the preceding claims, characterized in that the sensor device

(2) is configured to detect a mechanical vector quantity as the mechanical quantity (3) and the first one

Detection function a comparison of a direction of the mechanical vector size with a first direction range

(14) and the second recognition function comprises a

Comparison of the direction of the mechanical vector size with a second directional range (15) different from the first directional range (14).

5. Power tool (10; 20; 30) according to one of the preceding claims, characterized in that the first

Sensor device (2) is formed as the mechanical size (3) to detect a mechanical vector size and the first detection function, a comparison of a

Change in direction, in particular an angular velocity and / or a change angle, the mechanical vector size with a first direction change threshold value comprises and the second detection function comprises a comparison of

Change of direction with one of the first

Direction change threshold different second

Direction change threshold includes.

6. Power tool (20) according to claim 4 or 5, characterized in that the sensor device (2) comprises a measuring bearing (28) for detecting the mechanical vector size.

30113 / PCT. July 2017

A power tool (10; 20; 30) according to any one of the preceding claims, characterized in that the power tool (10; 20; 30) comprises user input means (5) adapted to input the function determination information by a user.

8. Power tool (10; 30) according to any one of the preceding claims, characterized in that the power tool (10; 60) via a communication interface (35) for

Communication with an external device (38), wherein the control device (4) is formed, the

Function determination information about the

Communication interface (35) to receive.

9. A power tool (10; 30) according to any one of the preceding claims, characterized in that the power tool (10; 60) has a user identification means (36), wherein the control means (4) is formed, the function determination information based on a means of the user identification means (36)

To provide identification of a user of the power tool (10; 60).

10. Power tool (10; 30) according to one of the preceding claims, characterized in that the sensor device (2) is formed, an operating and / or

Environment information, in particular a property of

Tool (1), a property of a workpiece (11) to be machined with the tool (1), a temperature and / or a humidity, wherein the control device (4) is configured, the function determination information based on the operating and / or or provide environmental information.

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11. Electric tool (10; 20; 30) after one of

preceding claims, characterized in that the control device (4) is designed to perform a calibration of at least one detection function.

12. Power tool (10; 30) according to one of the preceding claims, characterized in that the power tool (10; 20; 30) comprises a drive device (7) for driving the tool (1) and the control device (4)

is configured, in response to the detected kickback event, the drive means (7) to control to change the drive of the tool (1), in particular, to decelerate the tool (1).

13. Power tool (10; 30) according to one of the preceding claims, characterized in that the power tool

(10; 60) comprises a positioning device (29) which is designed to selectively place the tool (1) in a

Operating position or a safety position too

and the controller (4) is adapted to respond in response to the detected kickback event

Positioning device (29) to control, so that the tool

(1) is positioned in the safety position.

14. System comprising a power tool (10) according to any one of the preceding claims and an external device (38), in particular a server, wherein the power tool (10) is formed, to the external device (38) a

Operating and / or environmental information and / or a

User identification information to transmit and the external device (38) is formed based on the operating and / or environment information and / or the

User identification information

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July 24, 2017 Provide functional determination information and transmit to the power tool (10).

15. A method for detecting a kickback event of a power tool (10, 20, 30) with a rotatable tool (1) designed as a saw blade or milling cutter, comprising the steps of: detecting (S1) a mechanical quantity (3), the mechanical size (3) comprises a force, an acceleration, a speed, a deflection, a deformation and / or a mechanical tension and the

mechanical magnitude (3) depends on a force exerted by the tool (1), determining (S2) based on a

Function determination information, one to be used

Detection function of a first recognition function and a second recognition function and recognition (S3) different from the first recognition function, using the determined recognition function, the kickback event based on the detected mechanical quantity (3).

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